Brochure: Disinfection by-products in drinking water
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Chlorine is the most commonly used drinking water disinfectant. It has been used to disinfect water and make it suitable for drinking for more than 100 years. It has nearly eliminated diseases like typhoid fever, cholera, and dysentery in Canada.
The benefits of disinfecting drinking water with chlorine are much greater than the potential health risks of being exposed to higher levels of disinfection by-products.
Disinfection by-products called trihalomethanes (THMs) and haloacetic acids (HAAs) are formed naturally when chlorine in water combines with organic matter like leaves or other vegetation
THM and HAA levels tend to increase in the summer and fall
You don't have to stop using tap water. You can still brush your teeth, wash fruits and vegetables, use tap water to prepare foods, and wash dishes and clothes
You would have to be exposed to high levels of disinfection by-products over many years for your health to be at risk
You can be exposed by drinking or bathing in affected water or breathing in steam when showering
- Chlorine in drinking water in First Nations communities
- It's Your Health: Drinking Water Chlorination
- Questions and Answers on Drinking Water Devices
- Guidelines for Canadian Drinking Water Quality: Guideline Technical Document — Trihalomethanes
- Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Haloacetic Acids